Artificial teeth.



A. GYSI ARTIFICIAL TEETH;

APPLICATION FILED APR. 28, 1914.

Patented Oct. 15, 1918.

A LFRED G-YSI, OF

ARTIFICIAL TEETH.

ZURICH, SWITZERLAND, AssIeNoR ro'rnn DENTISTS SUPPLY comrm, A coRroRATIoN on NEW YORK.

Specification of Letters Patent.

Patented Got. 15, 1918.

Application filed April 28, 1914 Serial No. 834,901.

To all whom it may concern:

Be it known that I, ALFRED (Form, a citizen 7 of Switzerland, and resident of Zurich, Canton of Zurich, have invented'an Improvement in Artificial Teeth, of which the fol-- may secure results approximately commensurate with those of dentures for normal shaped jaws. j v In edentulous mouths, where the teeth have been out for approximately six years or longer, the upper. alveolar ridge has be come narrower and very much smaller than the lower ridge, which latter has become very little narrower, if changed at all. If,

in such a case, the upper and lower artificial molars would be set in proper inclination in the place directly over the alveolar ridges in order to prevent the tilting of the plates during mastication, the molars of the two plates would not meet'properly, and in some cases not meet at all. To overcome this difiiculty it has been a common practice to set the lower molars-so that they would overlap the upper molars bu'ccally, instead'of be ing overlapped by the uppers, a;s natureinf tended. This abnormal position of the molars has been known as crossbite. With the use of old-fashioned molars with their relatively flat mastication surfaces, this change of position was made without proper change of the form of the'mastication surface to suit the abnormal conditions; and

because of the flattened shape of the cusps heretofore employed, this was possible without causing the upper and lower molars to lock. 1

With the modern (so-called) anatomical molars, having greater biting power on ac-- count of their high cusps and deep grooves, which, in contacting upper and lower molars,

them more stable.

fit closely together, and making one very definite occlusal position alone possible, that is, the anatomical position (the upper molars overlappingthe lowers, buccally), the above arrangement of the teeth in the dentures to suit abnormal conditions ofthe'jaws could not be made.

' These anatomical molars could be placed in the abnormal crossbite position only by an elaborate grinding of the masticating or occlusal surface, by which grinding all the minor secondary cusps are lost and only the outer and the inner cusps can be retained; and this required that the advantages of these special teeth were lost, and instead, broad fiat occlusal surfaces produced which only crush the food, but no more bite or grind itthan in the older type of teeth.

For these reasons, the making of satisfactory crossbite dentures has been very little practised.- It required too much work on the part of the dentist; and at best, only insured bad biting power for the patient, The only real effect of the artificial teeth so made with overlapping under molars, was to make The main object of the-present application is to provide a new form of molars, namely, a form which closely resembles natural molars in appearance, though they have not been copied from nature, because in natural teeth forms for areal crossbite cannot be found (only malposition of the normally shaped molars) the crossbite molars set out in this application have been constructed after-tests and experiments based upon engi neering principles.

' :My invention consists in certain features of construction, more particularly in the oc-.

clusal surfaces of the teeth of the upper and lower jaws, ,whereby they jointly cooperate, both in vertical and transverse directions, to produce efi'ective mastication, the said construction beingfully described hereinafter and defined in the claims, reference being: bad tothe accompanying drawings which form apart of the specification.

In the drawings :-Figure 1 is a plan view of a denture comprising'the teeth of the lower jawand embodying my invention;

Fig. 2 is a similar view' of a denture comprising the teethof the upper jaw, also embodying my invention; Fig. 3 is a side elevation of the teeth of the-upper and lower jaws in occlusal relation; Fig. 4 is a cross sectional view on Fig. 3 taken on line 8-8; Fig. 5 is a longitudinal section taken on line t-t of Fig. 4; Fig. 6 is an elevation of the rear ends of the plates and rear molars, showing their cooperative action with a right lateral grinding movement of the lower jaw; and Figs. 7 and 8 are respectively perspective and rear elevation views of single teeth shaped for attachment to the plate and embodying my invention.

Except in respect to the occlusal surfaces, the general form of the teeth of my invention is immaterial; for example, the molars and bicuspids may be made as separate teeth or may be molded in block, that is, havin two molars and two bicuspids. In Figs. and 8 I have illustrated an example of an individual tooth, a molarof the lower jaw,

while in Fig. 4 I have indicated the block form of the teeth. In a general sense, the

' lower molars of my invention are the inverse 12 and 13, and with the longitudinal main groove 16 (between the cusps 8, 9 and 11 on the inner or lingual 'side and 12 and 13 on the outer or buccal side) arranged substantially one-third of the distance across the molar from the outside, otherwise designated as at the outer third of the mastication surface. This groove- 16 receives the outer cusps 8 and 16 of the upper posterior molar (Fig. 2). The transverse groove between the cusps 12 and 13 also receives the cusp 16 of the upper posterior molar, the cusp 8 of which is further received in the groove between the cusps 8, 13 and 9 of. the lower posterior molar. The groove 14, be-

., tween the cusps 8, 9, 10 of the lower posterior molar, receives the cusp 14 of the upper posterior molar; and similarly the groove 15 of the lower posterior molar receives the cusp 15 of'the upper posterior molar.

The general construction of the occlusal surfaces of the anterior molar of the lower jaw is much the same as that of the posterior molar above described, the differences being of minor importance, but preferably providin a recess 36 inthe anterior cusp 21. In this tooth, the general .arrangement of the cusps 18, 19, 20, 21, 22 and 23 and the grooves formed thereby, correspond approximately to the cusps 8, 9, 10, 11, 12 and 13 and the grooves formed thereby of the posterior molar; but in the case of the upper jaw, the anterior molar difl'ers considerably from the structure of the posterior .tweenthe whereby molar, as will be evident by referring to Fig. 2, this difference being due to the fact that the anterior molar of theupper jaw is required to coact with both of the posterior and anterior molars of the lower jaw instead of with the former alone.

Referring to the upper teeth, Fig. 2, the posterior molar has the cusps 8, 15, 16 and 14*, whereas the anterior molar has cusps 17 18 17 and 24, there being no cusp in the posterior molar positively corresponding to cusp 18. Moreover, the groove 11 between the cusps 17 and 18 is somewhat different, because in the anterior molar it is required to come farther outward toward the buccal side to provide for the cusp 18*. In articulating with the molars of the lower jaw the cusps 17 and 18 fit the space bethe lower aw (Fig. 3); the cusp 24 is received in the recess 24 formed by the juncture of the grooves between the cusps 19, 20, 21, 22 and 23 (and more particularly, groove between cusps 22 and 23) of the lower anterior molar (Fig. 1) the cusp 17 is received in the groove 17, between the cusps 18 and 20 of the lower anterior molar; and the cusp, 24 is received in the groove 24 between the cusps 19 and 20 of the lower anterior molar.

Coming now to a consideration of the bicuspids, these are each formed with the buccal and lingual cusps and with'pockets or recesses for catching and holding food it may be crushed by the teeth of the opposite jaw. In the case of the anterior bicuspids of the upper jaw, the lingual cusps may be greatly reduced or practically omitted when the pockets are employed. In the upper teeth the cusps 26 of the bicuspids, are joined by a transverse ridge 27 formed by secondary cusps, and upon each side of which are the food pockets 28. In the lower jaw, the posterior bicuspids approximate the upper bicuspids in having the pockets 31 and the separating secondary cus portions 30 as inner extensions of the mam cusps 29. The anterior bicuspids have the buccal cusps 32 but no pronounced lingual cusp, except as it may be said to be formed by the pocket formaosterior and anterior molars of tion 33 and the secondary cusps 34 between the pockets.

In the normal engagement or articulation of the upper and lower teeth the posterior bicuspid of the upper jaw is received in the space 27 a between the posterior bicuspid and anterior molar in the lower jaw; and the ant rior bicuspid of the upper jaw is received in the space 27 between the two bicuspids of the lower jaw (Fig. 3).

Having now described the general ar- 'rangement and make-up of the configuration of the improved teeth, I will now point out some of the more partlcular features of function and cooperation. By referring to inside of their buccal surfaces, as customary;

and moreover, these teeth are so shaped on their occlusal surfaces as to provide outwardly inclined surfaces over which the cusps of the upper molars may slide without fear of disengagement. Likewise, the cusps are so shaped that those of the upper and lower molars maintain engagement with lateral movements of the lower jaw in either direction (Fig. 6). This is possible by reason of the fact that the occlusal surfaces of the lower molars are made somewhat wider than those of the upper molars, so that while the outer or lingual cusps of the .lower molars permit lateral grinding action in the lingual direction from one side, the width of the V molars will maintain engagement of the molars on the opposite side of the jaw (Fig. 6

As the lower jaw, in moving from central position to one side or the other, also moves obliquely in the directions of the arrows w and 3 Fig. 1, and w and 3 Fig. 2, it fol- .lows that the trend or alinement' of the cusps and the grooves of the molars must also conform to this oblique alinement. By examining Fig. 1, it will be seen that the obliquely arranged arrows a: and y correspond to the alinement of the cusps 9, 10 and 13, also 11 and 12, also 19, 20 and 23, also 21 and 22; and furthermore, it is in alinement with the long inclined cusps 8 and 18 and similarly, to the trend of the transverse grooves between the cusps. This trend cooperates with the corresponding trend of the cusps and grooves in the upper molors, as indicated by the arrows m and This arrangement gives a grinding motion to the lower jaw from the buccal side inward and forward. On the opposite side, the lower -molars are supported or fulcrumed during the above motion and yet must have capacity for lateral movement to compensate; this provision is made by reason of the fact, that the cusps 14 and 17 are caused to go out of action and the cusps 9 and 19 respectively guided by the grooves 9 between the cusps 8 and 16 of the posterior molar and cusps 17 and 24 of the anterior molar of the upper jaw. This guidance is more nearly at right angles; and when this movement on the one side, is combined with the oblique movement on the other side, a pivotal action is had and the lower jaw is given a curved motion which facilitates the mastication function. I have indicated this lateral motion by the dotted arrows'ac and y". When the lower jaw is moving in the direction 00 on one side it is moving in the direction 00 on the other side.

This construction of the molars provides have shown several of such a large number of grinding cusp surfaces which enable a rapid breaking down and shearing of the food fibers; and likewise, the deep grooves or channels between the cusps provide pockets to hold the food in position during mastication. By the proper alining of the high cusps and deep grooves, there is no interlocking to interfere with mastication and hence the best possible results are secured without any mechanical or physical difficulty.

By providing pockets in the bicuspids thefood grains may be received and held while being crushed, and this will be more fully appreciated by reference to Fig. 5. In this view 5, is the anterior lower molar, and 6 and 7 the lower bicuspids,and similarly 5 6 and. 7 are respectively the anterior molar and bicuspids of the upper jaw. The grains are held in the spaces between the pockets 28 and 36-, 28 and 31, and 28 and 33 and are crushed by the action of the cusps 27, 30 and 34 of the bicuspids. This use of the pockets is extended to the molars at 35 and 36 and may be used as a secondary formation of any ofthe cusps. I have only shown a pocket 36 in the lower anterior molars, but in the upper molars I pockets, indicated at 35.

The crossbite molars herein described have some characteristic features which clearly distinguish them from the natural molars; among which may be noted :A lower natural molar has rounded outer or buccal cusps and pointed inner or lingual cusps; and with the longitudinal main groove, (separating outer and inner cusps) lying at the inner third of the molor. A lower crossbite of this invention has pointed outer cusps and rounded inner cusps, the longitudinal main groove being at approximately the outer third of the mastication surface. A similar distinction may be made between upper normal natural molars and lower artificial crossbite molars of this invention. The minor details of the mastication surface of these improved teeth are also very different from the natural and also from the artificial molars heretofore made. i For example: A lower natural molar has on the mastication surface, longitudinal and transversal grooves which are so formed as to divide this surface into four or five large main cusps (without counting the beauty marks or secondary, smaller cusps). In the lower crossbite molars of this invention, I have, on account of their reversed position and mastication movement, six large main cusps (not counting the beauty marks or secondary cusps). In the upper molars, the number of cusps in the improved teeth does not differ very markedly from the natural molars, but as the interdigitation of the upper cusps with natural teeth differs from the anatomical interdigitation andthe anatomical articulation movement, the inclination of theside walls forming the cusps in the natural teeth is very different from anatomical molars of this invention.

In order to facilitate the setting up of these new molar forms (crossbite forms) to which the dentists are not yet educated or familiar with, they are preferably manufactured, not only singly, but also. united together as asolid block, to which are also added the ordinary normal or anatomical bicuspids, so that the dentist has no difficulty in finding the proper relationship between the lower first crossbite molar and the upper'second normal bicuspid. This re lationship being so peculiar as to give to the upper row of bicuspids and molars a straight alinement or direction instead of the curved anatomical alinement, and to the lower row of bicuspids and molars a curved direction instead of the normal straight direction, a reversal of the usual lines.

I have shown my improved teeth in the plates for fitting the mouth so that a better understanding may be had of the nature of the invention and how the objects desired are secured, but it is to be understood that my improvements reside in the teeth, separately as well as collectively in combination. Furthermore, I desire it to be understood that I have shown the construction of the teeth in the form I have found most desirable in practice, but I do not restrict myself tothe exact details, as these may be varied without departing from the spirit of the invention, the more essential characteristics of which have been fully pointed out in the foregoing specification.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is

1. A denture for the lower jaw havin artificial .molars formed with cusps at Iooth their outer or buccal portions and inner or lingual portions, each molar having a longitudinal main groove arranged between said buccal and lingual cusps and at approximately the outer third of the mastication surface, and also having a plurality of'transverse grooves extending from said longitudinal main groove inwardly between the lingual cusps and toward the lingual side of the tooth. v

- 2. In cross-bite dentures comprising upper w and lower teeth, a lower set of molar teeth each having a longitudinal main groove arranged nearer the buccal side of the tooth than the lingual side and having that part of the mastication surface to the buccal side of the longitudinal main groove provided with a plurality of buccal cusps and that part of the mastication surface to the lintance across gual side of the longitudinal main groove provided with a plurality of lingual cusps greater in number and lower in height than the buccal cusps, comblned with an upper set. of molar teeth in which the teeth corresponding to the right and left sides of the jaw are arranged a distance apart less than the distance apart of the corresponding'molars in the lower set and said upper molars 'each provided with a plurality of cusps on the mastication surface whose longitudinal arrangement fits the longitudinal main grooves of the lower molars and also having othercusps 0n the lingual side of the mastication surface arranged to cooperate with the transverse grooved portions of the lower set of molar teeth. 3. In dentures for upper and lower jaws,

. the combination of lower molar teeth having a longitudinal main groove, six cusps upon buccal side of said upper molar teeth is of correspondingly less distance than the disfrom the.-right buccal side to the left buccal side of the lower molar teeth.

4;. In dentures for upper and lower aws, a set of lower molar teeth each having six main cusps upon its mastication surface with intervening grooved portions comprising a main longitudinal groove and transverse grooves and with two of the said cusps of each tooth occupying approximately the outer third of the mastication surface and arranged longitudinally on the buccal side of a longitudinal main groove, and in which also the general transverse trend of the cusps is diagonally forward, inward and downward, combined with upper molar teeth having the right and left sets arranged at a less distance apart than the molar teeth of the lower set, and each of said upper molar teeth further provided with less number of cusps upon its mastication surface across from the right buccal sideto the left than in the lower molar teeth, and said cusps lower set, and in which the general heights of the cusps decrease from the lingual to the buccal side, and the width across from the buccal sides of the right and left sets of said upper molar teeth is less than the corresponding distance across from the buccal sides of the right and left sets ofthe lower molar teeth.

6. An artificial molar for dentures, having its mastication surface divided by a longitudinal main groove at approximately the.

outer third of the mastication surface and also having on the buccal side of said longitudinal groove two high cusps and upon the lingual side of said longitudinal main groove a greater plurality of cusps of relatively less helght and positioned by a plurality of trans.

verse grooved portions.

7. An artificial molar for dentures, having its mastication surface provided with six clearly defined main cusps separated. by I grooved portions including a longitudinal main groove nearer to the buccal side than to the lingual side of the tooth, said main groove arranged to the lingual side of two of the main cusps and to the buccal side of the remainingfour main cusps.

8. An artificial molar for dentures, having its mastication surface provided with a longitudinal main. groove at approximately the outer third of the mastication surface, and further'havin two main cusps on the buccal side of said longitudinal main-groove and four main cusps at the lingual slde of the said longitudinal main groove and relatively positioned by transverse grooved portions and in which the general transverse tren of the alinement of the plurality of cusps is oblique with respect tothe longltudinal main groove.

9. An artificial molar for'crossbitej dentures, having its mastication surface-provided with a longitudinal main groove at approximately the outer third of the mastication surface, and further having two main cuspson the buccal side of said longitudinal main roove and four main cusps at the lingual side of the said longitudinal main groove and relatively positioned by trans- -yerse grooved portions, and inwhich there are three mam cusps arranged 1n an oblique direction transversely across the middle of the'jrliastication surface, two'main cusps arranged forward of the middle main cusps and 'one main cusp to the rear of the middle main cusps, and in which moreover, the general transverse arrangement of the cusps and grooves is inclined obliquely forward, inward and downward in respect to the position of the tooth in the mouth.

10. An artificial molar for crossbite dentures, havingjts mastication surface provided with six main cusps, separated into two buccal cusps and four lingual cusps by a longitudinal main groove arranged nearer the buccal side than the lingual side of the tooth, and in which the buccal cusps are relatively narrower transversely and higher than the lingual cusps.

11. In dentures, the combination of upper and lower bicuspids, each bicuspid having, intermediate'of its buccal andlingual cusp portions, a plurality of pockets or recesses separted by intermediate transverse minor cusp-portions, and said upper and lower bicuspids providing a plurality of opposed pockets for food arranged alternately with the minor cusp portions and bounded upon each side by the main cusps of the teeth.

12. In dentures, a lower set of molars andbicuspids in which the bicuspids and forward cus of the molars are each provided with poc ets in their mastication surfaces,

combined with an upper set of molars and bicuspids also having pockets in their mastication surfaces, the pockets of the two sets of teeth being so arranged that in the normal position of the sets of teeth the pockets of "the upper set are arranged substantially above the pockets of the lower set.

13. An artificial bicuspid for dentures having the buccal and lingual main cusps and two pockets arranged in the mastication surface between the said cusps and in longitudinal alinement and separated by a transverse portion constituting a minor cusp in respect to the pockets.

' 14. An upper artificial molar, having its mastication surface divided by a longitudinal main groove at approximately the middle thereof and having two main cusps to the buccal side of said oove and two main cusps to the lingual side thereof and said buccal cusps being arranged more anterior than the lingual cusps.

15. An upper artificial molar, having its mastication surface divided by a longitudinal main groove at approximately the middle thereof and having two main cusps to the buccal side of said oove and two main .cusps to the lingual slde thereof and said buccal cusps being arranged more anterior than the lingual cusps, and the posterior buccal cusp and anterior-lingual cusp meeting in the longitudinal groove and separating the anterior buccal cusp and the posgroove to provide a secondary cusp sepatended to the lingual side and providing rated from the anterior lingual cusp by a a secondary cusp at the lingual side. 10 transverse diagonal groove. In testimony of'which-invention, .I herew 17 An upper posterior molar having. unto set my hand. 5 three main cusps two buccal cusps and-one ALFRED GYSI,

lingual cusp, arranged in triangular rela- Witnesses: 1 tion by intervening transversely extending CARL GUBLER, grooves and the anterior buceal cusp ex- FRANK BoHR. 

